Free grinding device for steels and alloys



July 27; 1943. B. EGEBERG I FREE GRINDING DEVICE FOR STEELS AND ALLOYS Filed Nov. 12, 1940 INVENTOR. B/IE GER EGEBE/QG BY ATTORNEYS particularly good results by the as a part of thebody Patented July 27, 1943 2,325,180 FREE GRINDING nnvrcn FOR STEELS AND ALLOYS Birgei' Ezeberg,

corporation of Meriden, Conn., assignor to International Silver Company,

New Jersey Meriden, Conm, a

Application November 12, 1940, Serial No. 365,298 17 Claims. 51-295) The invention relates to the free grinding of steels and alloys and the like and to abrasive wheels therefor.

In the manufacture of articles of steel and alloy an particularly certain steels as, for example, articles of cutlery and fiat tableware, dimculties have been experienced with the use of the conventional grinding wheel in that the wheel was not of a sufficiently free cutting nature to avoid clogging with abraded steel to avoid searches and cracks. I have found that these difliculties are considerably reduced, if not entirely obviated, by intimately incorporating a the body of and with the particles of the grinding wheel so as to function as a lubricant at the very point or points of action between the particles of the grinding wheel and the work. I have obtained use of a sulphide such as molybdenum su1phide, -MoS2, which is present in suitable quantity with the particles thereof dispersed throughout the grinding body.

The relative the sulphide and ticuiar articles to be worked upon. In the manufacture of cutlery and tableware I have found that a grinding wheel embodying molybdenum sulphide of one part by weight of sulphide to marked advantages over the conventional abrasive wheel in that a freer cutting or grinding is'produced with the clogging by abraded metallic particles being substantially reduced or entirely obviated and with the scorches and cracks reduced or substantially eliminated.

The sulphide may be intimatel incorporated of the abrasive or grinding any suitable manner and according to the manufacture of a wheel embodying the invention I have used to good advantage a formula consisting of 6 to 6 /2 pounds of abrasive material (as for example No. 60 emery), 30 to 40 ounces of shellac (as for example commercial flake shellac), 8 ounces of common salt (coarse fine) and around 8 ounces of molybdenum sulphide.

The following procedure may be employed in the manufacture of the abrasive or grinding wheels: The abrasive material, the common salt, and the sulphide are mixed while in a thoroughly dry state as, for example, in a steam jacketed mixer, and after the thorough mixing ha been wheel in removed for use.

The constituents of the wheel including the lubricant itself are thus intimately mixed and bonded together to form a homogeneous, mass of abrasive and lubricant particles. The lubricant content may thus be adjusted to has also been found that by the mcorporation of molybdenum sulphide into the abrasive or grindmg wheel an increase of 20% or more in its life are obtained. The added cost of introducing the sulphide intothe wheel is thus more than compensated.

After such a wheel has its lowest point of safety, removed from the heat remeltedand been ground. down to the remainder can be iron ring and with suflicient eilected the shellac is added and thoroughly 5 range of 6 to 12 may be introduced with useiul mula is for the purpose .Bytheuseofmy grinding function corporation 'of be used amongst which may be mentioned the other natural resins, the synthetic resins (such as Bakelite), rubber (natural and artificial), etc.

The relative proportions of the sulphide or lubricant and the abrasive material used are determined to some extent by the purpose for which the grinding wheels are to instead of a ratio of one to twelve or thirteen parts of sulphide and abrasive material, I may employ substantially less or substantially greater relative proportions of the molybdenum sulphide, as for example, on to twenty or one to ten.

The incorporation of the molybdenum sulphide in other and altogether different formulae and differently bonded wheels than those set forth above substantially improves the wheels in the respects above described. For example, the sulphide may be incorporated in grinding or abrasive wheels made with sodium silicate, or in wheels of the hard vitrified type, and the molybdenum sulphide is particularly suitable as the lubricant to be employed because of its high melting point.

The invention also has utility as applied to set-up wheels, and good results have been obtained with wheels of this type embodying approximately one part of molybdenum sulphide to fourteen parts of emery by weight.

The common salt employed in the above forof providing for the desired porosity in the wheels and the desired cool cutting therein, that is, wheels less liable to burn at high speeds. This contributes to and enhances the advantage gained by the use of a lubricant. It is understood that any other equivalent material may be used for this purpose.

I am aware of the fact that molybdenum suiphide and other sulphur bearing materials, as well as selenium, have been used or proposed for be used. For example,

use as additions to steels in order to produce certain free machining and free grinding properties.

invention it is unnecessary to sulphides in the steels or steel metallic alloys, since the free is produced by the material inthe grinding or abrasive wheel incorporate such alloys or other corporated in itself. Moreover. some steels and alloys are rather sensitive to the addition of molybdenum sulphide and the like in that they acquire undesirable physical properties by reason or the inthe sulphides therein. For example, a high carbon variety of stainless steel is in this category, and it being impossible to obtain a high carbon steel of the free grinding variety which does not possess. the undesirable physical properties referred to, my invention is particularly useful in connection with the grinding and polishing of articles, as for example cutlery and fiat tableware, of high carbon stainless steels. The same applies to tool steels and to alloy steels diflicult to grind. Especially in the case of alloy addition, the heat conductivity of the steel is lowered and local overheating and cracking during grinding is induced. Such steels therefore require an exceptionally cool and free cutting grinding wheel. For the reasons indicated, however, the invention is not limited to the working of high carbon stainless steels or tool steels or alloy steels as it has the advantages and utility above set forth generally in this art.

A grinding wheel embodying the invention is illustrated in the drawing forming a part of this application. In this drawing- Fig. 1 is a segment of the face of a grinding wheel; and

Fig. 2 is a vertical cross section of the entire wheel on diametral axis D D of Fig. l.

The face of the wheel is shown as flat and perpendicular to its axis of rotation but it may be at any other angle, or concave or convex instead of fiat-depending on the nature of the work for which any particular wheel is intended.

The compressed grinding material A is mounted on the usual iron ring B having threaded holes C for receiving screws whereby the wheel is mounted on a shaft.

I claim:

1. A grinding wheel embodying molybdenum sulphide incorporated therein.

2. A grinding wheel embodying an abrasive material and a sulphide of a heavy metal as a lubricant incorporated therein in proportions of one part lubricant to ten to twenty parts abrasive material by weight.

3. A grinding wheel embodying an abrasive material and molybdenum sulphide intimately incorporated therein in proportions of one part to twenty parts of abrasive material, three to part of molybdenum six parts of binder, and one sulphide.

5. A grinding wheel embodying by weight 10 to 20 parts of abrasive material, 3 to 6 parts of. binder, 1 part of common molybdenum sulphide.

6. An abrasive device comprising a homogenous bonded mass of an abrasive material and a sulphide of a heavy metal of comparatively small particle size.

7. An abrasive device embodying an abrasive material, a sulphide of a heavy metal as a inbricant, and a porosity-giving substance bonded together to form a homogeneous mass.

8. An abrasive device having self-lubricating and the desired porosity qualities which are independently regulated both as to amounts and as to relative locations, formed of an intimate mixture of granular abrasive material, a sulphide of a heavy metal of comparatively small particle size, and a separate porosity-giving substance all bonded together in the original mix.

9. An abrasive device embodying an abrasive material and a sulphide of aheavy metal of comparatively small particle size intimately mixed 1 resins and rubber.

salt and 1 part of particle size, and a separate porosity-giving substance all bonded together in the original mix by a binder'of the class consisting of natural and synthetitc resins and rubber.

12. An abrasive device embodying an abrasive material and molybdenum sulphide of comparatively small particle ize intimately mixed and bonded with the abrasive material in the original mix.

13. An abrasive device embodying an abrasive material and iron sulphide of comparatively small particle size intimately mixed and bonded with the abrasive material in the original mix.

14. An abrasive device embodying an abrasive material and manganese sulphide of comparatively small particle size intimately mixed and bonded with the abrasivematerial in the original mix.

BIRGER EGEBERG. 

